JP2003162045A - Lithographic printing original plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photosensitive lithographic printing original plate for IR laser for direct plate making which has excellent stability of the coating liquid, which is not limited for the place of handling and which has preferable discrimination developing property, developing stability, development latitude and printing durability. <P>SOLUTION: The lithographic printing original plate has an image recording layer formed on a supporting body, with the image recording layer containing a substance which absorbs light to generate heat, a resin soluble with an alkali aqueous solution and having a phenolic hydroxyl group, and a polyvinyl acetal resin having an acid group of pKa≤5. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording / printing master plate material that can be used as an offset printing master, and in particular, a digital image signal produced by a computer and output can be recorded by an infrared laser beam to directly make a plate. The present invention relates to a positive photosensitive printing original plate material for infrared laser for so-called direct plate making.

[0002]

2. Description of the Related Art Conventionally, as a system for directly making a plate from digital data of a computer, an electrophotographic method, a photopolymerization system by a combination of Ar laser exposure and post-heating, and a silver salt sensitive material laminated on a photosensitive resin are used. There are known ones, such as a silver master type, a discharge master, and a method in which a silicone rubber layer is destroyed by laser light.

However, in the method using the electrophotographic method, the processing such as charging, exposure and development is complicated, and the apparatus becomes complicated and large-scale. This method requires a post-heating step and also requires a highly sensitive plate material, which makes it difficult to handle in a bright room. The methods (1) and (2) have the drawback that the processing becomes complicated and the cost becomes high because a silver salt is used. Although the other method is a method with a relatively high degree of perfection, it has a problem in removing the silicone residue remaining on the plate surface. On the other hand, the development of lasers in recent years has been remarkable, and particularly for solid-state lasers / semiconductor lasers having an emission region from near infrared to infrared, high-output and small-sized devices have become easily available.
These lasers are very useful as an exposure light source when making a plate directly from digital data of a computer or the like.

In a conventionally known positive type lithographic printing plate material for infrared laser for direct plate making, an alkali aqueous solution-soluble resin having a phenolic hydroxyl group such as novolac resin is used as an alkali aqueous solution-soluble polymer compound. This positive-type lithographic printing plate precursor changes the association state of the cresol novolac resin due to the action of heat in the exposed region of the photothermal conversion agent, and therefore the difference in the behavior between the exposed part and the non-exposed part due to the heat makes the solubility distinctive. Occurs, which causes plate making, but due to the narrow difference in dissolution rate,
In the actual plate-making work, it was susceptible to slight fluctuations in alkali activity and lacked stability. Therefore, the development of a technique for expanding the development latitude with an alkali dissolution inhibitor (dissolution inhibitor) is being actively carried out. A resist material containing is disclosed, and WO99
/ 11458A (KPG) has proposed a composition containing a polymer having a specific pendant group (hydroxyl group, carboxylic acid) as a dissolution inhibitor, and JP-A-10-87733 (Konica) discloses the composition. , A orthocarboxylic acid as a dissolution inhibitor, an acetal, a polymer having one or more graft side chains of ketal, and a printing original plate containing a photoacid generator are disclosed, EP1072404A (Lastr
The a) publication discloses an image recording material containing a partially esterified hydroxyacrylic polymer. However, the above-mentioned printing plate materials are still insufficient in distinguishability.

Further, in Japanese Patent Laid-Open No. 7-285275, a substance which absorbs light and generates heat, various onium salts, quinonediazide compounds and the like are added to an alkali aqueous solution soluble resin having a phenolic hydroxyl group such as a novolac resin. The image recording material added is proposed. In these image-recording materials, onium salts, quinonediazide compounds, etc. in the image portion act as dissolution inhibitors that substantially reduce the solubility of the alkali aqueous solution-soluble resin, and in the non-image portion they are decomposed by heat to dissolve inhibitors. It does not work as an image forming. However, in this image recording material, onium salts, quinonediazide compounds, and the like have a light absorption region (350 to 500 nm) in the visible region, so that the handling place is inconveniently limited to yellow lights. Further, in order to make the obtained printing plate usable for a longer period of time, it is necessary to wash it with a solvent such as a cleaner liquid so that it can be reused. There is a problem in that printing durability is deteriorated when a cleaner liquid is used.

On the other hand, Japanese Patent Laid-Open No. 7-285275 describes that an acrylic resin or a urethane resin can be used on the assumption that an onium salt, a quinonediazide compound or the like is added. According to this publication, acrylic resin and urethane resin have no description of dissolution inhibiting property or accelerating property with respect to an alkaline aqueous solution-soluble resin having a phenolic hydroxyl group, and are not intended to prevent dissolution, but improve durability of the printing plate. It is disclosed that this can be done.

Further, the insolubilization of the outermost surface layer due to the hardening reaction of novolak has the effect of expanding the development latitude, and it is also possible to add an epoxy compound to accelerate the curing.
It is described in the official gazette. Further, JP-A No. 11-338131 discloses that development stability can be improved by using an anionic metal complex having a thermally decomposable counter cation as an infrared absorber.

On the other hand, JP-A-10-153863 discloses that the stability of developability can be improved by using a specific metal complex or salt together with a specific binder having a hydrophilic group. . Further, in JP-A-2001-92126, the mechanism of action is unknown, but as a dissolution inhibitor,
The use of organic compounds of inorganic salts of Group IIIA or transition metals is disclosed. However, it is considered that the increase in the effect of distinguishing the solubility shown in these disclosed techniques is due to the appearance of the dissolution inhibiting effect due to the interaction between the binder and the metal compound. It is also recognized that the development stability of the light-sensitive material and the reproducibility of the development latitude are reduced due to the stability of the photosensitive material and the influence of the heat history during coating and drying on the performance.

As described above, the conventionally known positive type lithographic printing plate for infrared laser for direct plate making is solvent resistant and visible light safe in order to enhance the distinguishability between the image part and the non-image part. It was in a situation where the practically necessary incidental characteristics such as durability, durability, and manufacturing stability were not involved.

[0010]

The present invention has been made from such a background, and therefore, an object of the present invention is to provide a printing original plate containing an alkali aqueous solution-soluble resin having a phenolic hydroxyl group and a photothermal conversion agent. Is to solve the above-mentioned problems by improving the image forming property and the production stability and plate making workability. Specifically, the stability of the coating liquid is excellent, there is no restriction on the handling place, and the distinctive development is performed. To provide a positive photosensitive lithographic printing plate precursor for an infrared laser for direct plate making, which has good printing property, development stability and development latitude, and good printing durability.

[0011]

Means for Solving the Problems The inventors of the present invention have made earnest studies to solve the above-mentioned problems that impair the practical properties of the lithographic printing plate, and found that a polyvinyl acetal resin having an acid group of pKa of 5 or less was used as the plate. It was found that the inclusion in the image recording layer is effective in suppressing the above defects.
Based on this finding, further research was conducted to reach the present invention. That is, the present invention provides the following lithographic printing plate precursor.

1. An image recording layer containing a substance that absorbs light and generates heat, an alkali aqueous solution-soluble resin having a phenolic hydroxyl group, and a polyvinyl acetal resin having an acid group of pKa of 5 or less is provided on a support. An original plate for lithographic printing.

2. The polyvinyl acetal resin is 1,
2. The lithographic printing plate precursor as described in 1 above, which is a polyvinyl acetal resin having an ester bond group with an organic acid selected from 2-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, phthalic acid and trimetritic acid.

A feature of the present invention is that a polyvinyl acetal resin having an acid group of pKa5 or less is further contained in an image recording layer containing a substance which absorbs light and generates heat and an alkali aqueous solution-soluble resin having a phenolic hydroxyl group. (Hereinafter, referred to as “acid-modified polyvinyl acetal resin”). In the present invention, the acid-modified polyvinyl acetal resin contained is effective in specifically improving the development latitude. If an unmodified polyvinyl acetal resin having no acid group is used, the effect of improving the development latitude cannot be obtained. From these, when the acid-modified polyvinyl acetal resin is used, it is considered that the acid group improves the adhesion of the substrate while maintaining the alkali elution property, and as a result, the development latitude can be improved. .

According to the present invention, the solubility of the alkali aqueous solution-soluble resin in the image area is lowered due to the interaction between the alkali aqueous solution-soluble resin having a phenolic hydroxyl group represented by novolac resin and the acid-modified polyvinyl acetal resin. Therefore, the distinguishability is improved, and the development latitude is surprisingly improved. Therefore, in the visible region such as onium salts and quinonediazide compounds, the light absorption region (350
It is not necessary to add a compound having ˜500 nm), and therefore it can be used under a white light, and there is no inconvenience that the handling place is limited to a yellow light. In addition, by forming a crosslinked hard film at the outermost layer, the solvent resistance of the printing plate is greatly improved, and it is possible to use a cleaner liquid for the printing plate or use ink containing a special solvent such as UV ink. All of these defects of the above-mentioned prior art are eliminated.

As described above, Japanese Patent Application Laid-Open No. 10-87733 discloses a printing original plate containing a polymer having a graft side chain such as orthocarboxylic acid and a photoacid generator. Then, by setting the pKa of the acid group of the acid-modified polyvinyl acetal resin to be used to be 5 or less, an excellent discrimination effect can be obtained even without the presence of a photoacid generator, and the photothermal conversion effect was utilized. A master plate with excellent performance for lithographic printing is obtained.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. [Acid-modified polyvinyl acetal resin] The acid-modified polyvinyl acetal resin used in the present invention is a polyvinyl acetal resin having an acid group having a pKa (dissociation constant) of 5 or less, and generally, polyvinyl acetal resin has pKa
It is a resin obtained by introducing 5 or less acid groups for modification. This acid-modified polyvinyl acetal resin is
It is a resin that is soluble or swellable in an alkaline aqueous solution. The amount of acid groups introduced into the acid-modified polyvinyl acetal resin is generally such that the acid content per 1 g of the resin is 0.
A range of 1 to 6 meq is suitable. When the acid content per 1 g of the resin is less than 0.1 meq, the developability with an alkali developing solution becomes insufficient, and when it is more than 6 meq, abrasion resistance deteriorates. The preferred acid content per gram of resin is 0.5
~ 4 meq.

Specific examples of the acid-modified polyvinyl acetal resin used in the present invention include Japanese Patent Application Nos. 60-109122 and 60.
-123863, 60-198742 polyvinyl acetal resins as described in the reaction with an intramolecular acid anhydride of an organic polycarboxylic acid, further containing a hydroxyl group or a cyano group The thing which introduced the component etc. is mentioned. Particularly preferred acid-modified polyvinyl acetal resin is represented by the following general formula (I). General formula (I)

[0019]

[Chemical 1]

In the formula, R ₁₀ is an alkyl group which may have a substituent or a hydrogen atom, R ₁₁ is an alkyl group which does not have a substituent, and R ₁₂ is an aliphatic or aromatic carbon atom having a carboxylic acid group. A hydrogen group, R ₁₃ is an aliphatic or aromatic hydrocarbon group which has at least one hydroxyl group or nitrile group and may further have another substituent,
n ₁ , n ₂ and n ₃ , n ₄ , n ₅ represent mol% of each recurring unit,
The ranges are as follows. n ₁ = 5 to 85, n ₂ = 0 to 60, n ₃ = 0 to 20, n ₄ = 3 to 60, n ₅
= 0 to 60.

The resin represented by the above general formula (I) is obtained by acetalizing polyvinyl alcohol with an aldehyde, further reacting the residual --OH with an acid anhydride, and further producing a part of the generated carboxylic acid by a hydroxyl group or a cyano group. It is obtained by reacting with a halogen compound having The resin of the general formula (I) is mainly composed of five components, a vinyl acetal component as the first component, a vinyl alcohol component as the second component, an unsubstituted ester component as the third component, and a fourth component as the fourth component. An ester component containing a carboxyl group, and a fifth component is an ester component containing a hydroxyl group or a cyano group, and each component may have at least one structural unit.

The vinyl acetal component as the first component is
An aliphatic aldehyde which may have a substituent is reacted with a vinyl alcohol component, and as the substituent, a carboxyl group, a hydroxyl group, a chloro group, a bromine group, 3
Examples thereof include a primary amino group, an alkoxyl group, a cyano group, a nitro group, an amide group, an ester group, a urethane group and a ureido group. Specifically, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, pentyl aldehyde, hexyl aldehyde, glyoxylic acid, N, N-dimethylformamide di-n-butyl acetal, bromoacetaldehyde, chloracetaldehyde, 3-hydroxy-n-butyraldehyde. , 3-methoxy-n-butyraldehyde, 3- (dimethylamino)
Examples include, but are not limited to, -2,2-dimethylpropionaldehyde, cyanoacetaldehyde, and the like.

In the unsubstituted ester component which is the third component, the substituent R ₁₁ represents an alkyl substituent having 1 to 10 carbon atoms, and a methyl group and an ethyl group are particularly preferable from the viewpoint of developability.

In the ester component containing a carboxyl group which is the fourth component, R ₁₂ is an aliphatic carboxylic acid or aromatic carboxylic acid group having 1 to 20 carbon atoms, and these are mainly succinic anhydride and maleic anhydride. , Phthalic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, 1,
2-cyclohexanedicarboxylic acid, anhydrous cis-4-cyclohexene 1,2-dicarboxylic acid is obtained by reacting an acid anhydride and the residual -OH of polyvinyl acetal,
Other cyclic acid anhydrides may be used. Among these acid anhydrides, anhydrides of 1,2-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, phthalic acid and trimetritic acid are preferable. Further, R ₁₂ may have a substituent other than the carboxy group. As the substituent, -OH, -C≡N, and a group represented by the following general formula,

[0025]

[Chemical 2]

In addition, —Cl, —Br, —NO ₂ , —OR _{14 and the} like can be mentioned. R ₁₄ has 1 carbon atom which may have a substituent.
To 20 alkyl groups, aralkyl groups, aryl groups and the like, and the substituents are -OH, -C≡N, -Cl,
-Br, such as -NO _2, and the like.

In the ester component containing a hydroxyl group or a cyano group as the fifth component, R ₁₃ is esterified by reacting the carboxylic acid in R _{12 of} the fourth component with a halogen compound containing a hydroxyl group or a cyano group. Can be obtained. Specific examples of R ₁₃ include, but are not limited to, groups represented by the following general formula.

[0028]

[Chemical 3]

[0029]

[Chemical 4]

[0030]

[Chemical 5]

[0031]

[Chemical 6]

[0032]

[Chemical 7]

In the acid-modified polyvinyl acetal resin represented by the general formula (I), n ₁ is preferably 5 to 85 mol%, particularly preferably 25 to 70 mol%. As the value of n ₁ becomes smaller, the film strength becomes weaker, and as the value of n ₁ becomes larger, other components eventually decrease and adversely affect. With respect to n ₄ , 3 to 60 mol% is preferable, and 10 to 55 mol% is particularly preferable. When the value of n ₄ is large, the swelling of the exposed portion with the alkali developing solution is large, and when the value of n ₄ is small, it is difficult to develop with the alkali developing solution and the film is removed. With respect to n _5, it is preferably more than 0 and 60 mol% or less, and particularly preferably more than 0 and 40 mol% or less. As the value of n ₅ increases, other components eventually decrease and adversely affect.

The molecular weight of the above acid-modified polyvinyl acetal resin is suitably about 5,000 to 400,000 as measured by gel permeation chromatography, preferably about 50,000 to 300,000. These acid-modified polyvinyl acetal resins may be used alone or in combination. Further, in the present invention, these acid-modified polyvinyl acetal resins may be mixed with other resins in an amount of 50% by weight or less based on the resin, if necessary. Examples of the resin to be mixed include a polyurethane resin having no carboxyl group, a polyvinyl acetal resin which is not acid-modified, a polyamide resin, an epoxy resin, an acrylic resin, a methacrylic resin, a polystyrene resin, a novolac phenolic resin, and the like. You can Further, in the present invention, the acid-modified polyvinyl acetal resin is
Generally, it is used in a proportion of 0.5 to 20% by mass, preferably 1.0 to 10% by mass, based on the total solid content of the printing plate material.

[Alkaline Aqueous Solution Soluble Resin Having Phenolic Hydroxyl Group] Examples of the alkaline aqueous solution soluble resin having a phenolic hydroxyl group (hereinafter, referred to as “resin having a phenolic hydroxyl group”) used in the present invention include, for example, phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p-, or m- /
Novolak resins such as mixed formaldehyde resins may be mentioned.

The resin having a phenolic hydroxyl group preferably has a weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 10,000. Further, as described in U.S. Pat. No. 4,123,279, a condensate of formaldehyde with a phenol having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin. You may use together. The resin having such a phenolic hydroxyl group may be one type or two types.
You may use it in combination of 2 or more types.

As one aspect of the present invention, a copolymer containing the above-mentioned resin having a phenolic hydroxyl group and 10 mol% or more of at least one of the following (a) to (c) as a copolymerization component (hereinafter referred to as " A specific copolymer ")) may be used in combination. This specific copolymer, when coexisting with the acid-modified polyvinyl acetal resin, has the action of increasing the dissolution rate of the non-image area and improving the identification and development effect without promoting the solubility of the image area. There is. It is presumed that this action is due to the structural feature having both a sulfone group and an imide group, and such a favorable effect was not observed in other general solvent-soluble binder polymers.

(A) Monomer having a sulfonamide group having at least one hydrogen atom bonded to a nitrogen atom in one molecule (b) Monomer having an active imino group represented by the following formula in one molecule

[0039]

[Chemical 8]

(C) Acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, or hydroxystyrene each having a phenolic hydroxyl group.

The specific copolymer used in the present invention is required to contain at least one of the above (a) to (c) as a copolymerization component in an amount of 10 mol% or more.
Those containing more than mol% are more preferable. If it is less than 10 mol%, the interaction with the resin having a phenolic hydroxyl group becomes insufficient and the development latitude decreases. Further, it may contain a copolymerization component other than the above (a) to (c).

The monomer corresponding to (a) is a low molecular weight compound having in each molecule one or more sulfonamide groups having at least one hydrogen atom bonded to a nitrogen atom and one or more polymerizable unsaturated bonds. It is a monomer consisting of.
Among them, a low molecular weight compound having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or mono-substituted aminosulfonyl group or a substituted sulfonylimino group is preferable. Examples of such compounds include compounds represented by the following general formulas (II) to (VI).

[0043]

[Chemical 9]

In the formula, X ¹ and X ² are each --O-- or-
NR ¹⁰ − is shown. R ^4, R ⁷ each is a hydrogen atom or a -C
Represents H ₃ . R ⁵ , R ⁶ , R ¹² , R ¹⁵ , and R ¹⁹ each represent an alkylene group having 1 to 12 carbon atoms, which may have a substituent, a cycloalkylene group, an arylene group, or an aralkylene group. R ⁵ , R ¹⁰ and R ¹⁶ are each a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms,
A cycloalkyl group, an aryl group or an aralkyl group is shown. R ⁹ and R ²⁰ each represent an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group which may have a substituent. R ¹¹ , R ¹³ , R
¹⁷ represents a hydrogen atom or -CH _3. R ¹⁴ and R ¹⁸ are each a single bond or a carbon atom which may have a substituent.
Represents an alkylene group, a cycloalkylene group, an arylene group or an aralkylene group. Y ^1, Y ² each represents a single bond or CO-.

Specifically, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

The monomer corresponding to (b) is a monomer composed of a low molecular weight compound having one or more active imino groups represented by the above formula and one or more polymerizable unsaturated bonds in one molecule. As such a compound, specifically, N- (p-toluenesulfonyl) methacrylimide, N- (p-toluenesulfonyl) acrylimide, or the like can be preferably used.

The monomer corresponding to (c) is a monomer composed of acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, or hydroxystyrene each having a phenolic hydroxyl group. Specific examples of such a compound include N- (4
-Hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide, o-hydroxyphenyl acrylate, m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxyphenyl methacrylate, m-hydroxyphenyl methacrylate, p-hydroxy Phenyl methacrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene and the like can be preferably used.

As the other copolymerization component, for example, the following monomers (1) to (12) can be used. (1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate. (2) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate, N-dimethylaminoethyl Alkyl acrylate such as acrylate. (3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl. Alkyl methacrylate such as methacrylate.

(4) Acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N -Acrylamide or methacrylamide such as ethyl-N-phenylacrylamide. (5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether and phenyl vinyl ether.

(6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate. (7) Styrenes such as styrene, α-methylstyrene, methylstyrene and chloromethylstyrene. (8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone. (9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene. (10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like. (11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, and N- (p-chlorobenzoyl) methacrylamide. (12) acrylic acid, methacrylic acid, maleic anhydride,
Unsaturated carboxylic acids such as itaconic acid.

The specific copolymer used in the present invention preferably has a weight average molecular weight of 2000 or more and a number average molecular weight of 1000 or more. More preferably, the weight average molecular weight is 5,000 to 300,000 and the number average molecular weight is 2,000 to.
It is 250,000 and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10.

The specific copolymer may be used alone or in combination of two or more kinds.

The compounding weight ratio of the above-mentioned resin having a phenolic hydroxyl group to the above-mentioned specific copolymer is 50:50 to 5: 5.
Preferably in the range of 95, 40:60 to 1
More preferably, it is in the range of 0:90. When the compounding amount of the resin having a phenolic hydroxyl group is larger than this, the sea-island structure is reversed and it becomes difficult to improve the solvent resistance and the like. On the contrary, when the blending amount of the copolymer is larger than that, the surface layer of the resin having the phenolic hydroxyl group becomes too thin, and the development latitude is insufficiently improved.

These alkali-soluble polymer compounds composed of a resin having a phenolic hydroxyl group and a specific copolymer may be used either individually or in combination of two or more, and they may be used in the total solid content of all printing plate materials. , 30-99
It is used in an amount of 50% by weight, preferably 40 to 95% by weight, particularly preferably 50 to 90% by weight. When the amount of the alkali-soluble polymer compound added is less than 30% by weight, the durability of the recording layer deteriorates, and when it exceeds 99% by weight, both the sensitivity and the durability are unfavorable.

[Substance that Absorbs Light and Generates Heat] In the present invention, various pigments or dyes can be used as the substance that absorbs light and generates heat. As a pigment,
Commercial pigment and color index (CI) handbook,
"Latest Pigment Handbook" (edited by Japan Pigment Technology Association, 1977), "Latest Pigment Application Technology" (CMC Publishing, 1986), "Printing Ink Technology" CMC Publishing, 1984)
The pigments described in 1. can be used.

The types of pigments include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments,
Blue pigment, green pigment, fluorescent pigment, metal powder pigment, etc.
Polymer bound dyes may be mentioned. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments,
Perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, dyed lake pigments,
Azine pigment, nitroso pigment, nitro pigment, natural pigment, fluorescent pigment, inorganic pigment, carbon black and the like can be used.

These pigments may be used without surface treatment or may be subjected to surface treatment before use. The surface treatment method includes a method of surface-coating a resin or wax, a method of attaching a surfactant, a method of binding a reactive substance (for example, a silane coupling agent, an epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are "property and application of metal soap" (Koshobo), "printing ink technology" (CMC Publishing, 1984) and "latest pigment application technology" (CMC Publishing, 1986).
Annual publication).

The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably 0.1 μm to 1 μm.
It is preferably in the range of. Particle size of pigment is 0.01μ
When it is less than m, it is not preferable from the viewpoint of stability of the dispersion in the coating liquid for the photosensitive layer, and when it exceeds 10 μm, it is not preferable from the viewpoint of uniformity of the photosensitive layer. As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production or the like can be used. As the disperser, ultrasonic disperser, sand mill, attritor, pearl mill, super mill,
A ball mill, an impeller, a despather, a KD mill, a colloid mill, a dynatron, a three roll mill, a pressure kneader and the like can be mentioned. For details, see "Latest Pigment Application Technology."
(CMC Publishing, published in 1986).

As the dye, commercially available dyes and literatures (for example, "Dye Handbook" edited by the Society of Organic Synthetic Chemistry, published in 1970)
The publicly known ones described in 1) can be used. Specific examples include dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. In the present invention, among these pigments or dyes, those that absorb infrared light or near infrared light are particularly preferable because they are suitable for use in a laser that emits infrared light or near infrared light.

Carbon black is preferably used as such a pigment that absorbs infrared light or near infrared light. Examples of dyes that absorb infrared light or near infrared light include JP-A-58-125246 and JP-A-59.
-84356, JP-A-59-202829, JP-A-60-78787 and the like,
JP-A-58-173696, JP-A-58-18169
No. 0, methine dyes described in JP-A-58-194595, JP-A-58-112793, and JP-A-58.
-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744 and the like, and JP-A-58-112792. Examples thereof include squarylium dyes and cyanine dyes described in British Patent 434,875.

Further, as dyes, US Pat. No. 5,156,
The near-infrared absorption sensitizer described in US Pat. No. 938 is also preferably used, and the substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, JP-A-57-1.
No. 42645 (US Pat. No. 4,327,169), a trimethine thiapyrylium salt, JP-A-58-1810.
No. 51, No. 58-220143, No. 59-41363.
No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, and the pyrylium compounds described in JP-A-59-2161.
Cyanine dye described in US Pat. No. 4,283,4
No. 75, pentamethine thiopyrylium salt, etc., and the pyrylium compounds disclosed in Japanese Examined Patent Publication Nos. 5-13514 and 5-19702, Epolight III-1.
78, Epolight III-130, Epolight
t III-125 and the like are particularly preferably used.

Further, as another particularly preferable example of the dye, there can be mentioned near infrared absorbing dyes described as formulas (I) and (II) in US Pat. No. 4,756,993. These pigments or dyes are used in an amount of 0.01 to 50% by weight, preferably 0.1 to 10% by weight, and particularly preferably 0.5 to 10% by weight, in the case of pigments, based on the total solid content of the printing plate material. Particularly preferably 3.1
It can be added to the printing plate material in a proportion of from 10 to 10% by weight. If the amount of the pigment or dye added is less than 0.01% by weight, the sensitivity will be low, and if it exceeds 50% by weight, the uniformity of the photosensitive layer will be lost and the durability of the recording layer will be poor. These dyes or pigments may be added to the same layer as other components, or may be added to another layer provided separately. When it is formed as a separate layer, it is desirable to add it to a layer adjacent to a layer containing a substance which is to be described later and is a substance which substantially decomposes the solubility of the binder in the state of being thermally decomposable and not decomposed. The dye or pigment and the binder resin are preferably in the same layer, but may be in different layers.

[Other Components] In forming the above-mentioned positive image recording layer, in addition to the above-mentioned essential components, various additives may be further added, if necessary, as long as the effects of the present invention are not impaired. Can be added. For example, an onium salt, an o-quinonediazide compound, an aromatic sulfone compound, an aromatic sulfonic acid ester compound, or the like, which is thermally decomposable, is used in combination with a substance that substantially reduces the solubility of the alkaline water-soluble polymer compound when not decomposed. Doing so is preferable from the viewpoint of improving the dissolution inhibiting property of the image area in the developing solution. As the onium salt, a diazonium salt,
Examples thereof include ammonium salt, phosphonium salt, iodonium salt, sulfonium salt, selenonium salt, arsonium salt and the like.

Suitable onium salts used in the present invention include, for example, SI Schlesinger,
Photogr. Sci. Eng., 18, 387 (1974), TS Bal et a
l, Polymer, 21, 423 (1980), JP-A-5-158230
Diazonium salt described in U.S. Pat. No. 4,069,055
No. 4,069,056, ammonium salts described in JP-A-3-140140, DC Necker et al, Macromolecul
es, 17, 2468 (1984), CS Wen et al, Teh, Proc. Co
nf.Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat.
(6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31.
(1988), European Patent 104,143, U.S. Patent 339,049.
No. 410,201, JP-A No. 2-150848, and JP-A No. 2-2965.
Iodonium salt described in No. 14, JVCrivello et al, P
olymer J. 17, 73 (1985), JV Crivello et al. J.
Org. Chem., 43, 3055 (1978), WR Watt et al, J. P.
olymer Sci., Polymer Chem. Ed., 22, 1789 (1984),
JV Crivello et al, Polymer Bull., 14, 279 (198
5), JV Crivello et al, Macromorecules, 14 (5),
1141 (1981), JV Crivello et al, J. Polymer Sci.,
Polymer Chem. Ed., 17, 2877 (1979), European Patent 37
0,693, 233,567, 297,443, 297,442
U.S. Pat.Nos. 4,933,377, 3,902,114, 410,
No. 201, No. 339,049, No. 4,760,013, No. 4,734,444
No. 2,833,827, German Patent Nos. 2,904,626, 3,60
Sulfonium salts described in 4,580 and 3,604,581, J.
V. Crivello et al, Macromorecules, 10 (6), 1307 (19
77), JV Crivello et al, J. Polymer Sci., Polyme
r Chem. Ed., 17, 1047 (1979), selenonium salt, CS Wen et al, Teh, Proc.Conf. Rad. Curing AS
Examples include arsonium salts described in IA, p478 Tokyo, Oct (1988). Among the onium salts, the diazonium salt is particularly preferable. Further, particularly preferable diazonium salts include those described in JP-A-5-158230.

As counter ions of the onium salt, tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5
-Sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2
-Nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfonic acid, 2-methoxy-4-hydroxy-5- Examples thereof include benzoyl-benzenesulfonic acid and paratoluenesulfonic acid. Among these, alkylaromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid are particularly preferable.

Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide assists the solubility of the light-sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder by thermal decomposition and the effect of changing o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include those described in J. The compounds described on pages 339 to 352 of "Light-Sensitive Systems" (John Wiley & Sons. Inc.) by Coser can be used, but in particular, they have been reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. -Sulfonic acid esters or sulfonic acid amides of quinonediazide are preferred. Further, benzoquinone (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,3) as described in JP-B-43-28403.
2) -Diazido-5-sulfonic acid chloride ester with pyrogallol-acetone resin, US Pat. No. 3,046,12
0 and benzoquinone- (1,2) -diazide sulfonic acid chlorides or naphthoquinone- (1,2) -diazide-5-sulfonic acid chlorides and esters of phenol-formaldehyde resins described in No. 3,188,210 It is preferably used.

Further, an ester of naphthoquinone- (1,2) -diazide-4-sulfonic acid chloride and a phenol formaldehyde resin or a cresol-formaldehyde resin, naphthoquinone- (1,2) -diazide-
Esters of 4-sulfonic acid chloride and pyrogallol-acetone resin are likewise preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, and JP-A-48-96.
575, JP-A-49-38701, JP-A-48-13354, JP-B-41-11222, JP-B-45-9610, JP-B-49-17481
U.S. Pat.Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495.
No. 3,785,825, British Patent No. 1,227,602, No.
1,251,345, 1,267,005, 1,329,888,
Mention may be made, for example, of those described in the respective specifications such as 1,330,932 and German Patent No. 854,890.

The amount of the o-quinonediazide compound added is preferably 1 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 3% by mass based on the total solid content of the printing plate material.
It is in the range of 0 mass%. These compounds can be used alone, but may be used as a mixture of several kinds.

Further, cyclic acid anhydrides, phenols and organic acids may be used in combination for the purpose of further improving the sensitivity. Examples of the cyclic acid anhydride include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, and anhydride described in U.S. Pat. No. 4,115,128. Maleic acid, chloromaleic anhydride,
α-Phenyl maleic anhydride, succinic anhydride, pyromellitic dianhydride, etc. can be used. As phenols,
Bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone,
4-hydroxybenzophenone, 4,4 ', 4 "-trihydroxytriphenylmethane, 4,4', 3", 4 "
-Tetrahydroxy-3,5,3 ', 5'-tetramethyltriphenylmethane and the like. Further, as organic acids, sulfonic acids, sulfinic acids, alkylsulfates, phosphonic acids, phosphoric acid esters, carboxylic acids and the like described in JP-A-60-88942 and JP-A-2-96755 are mentioned. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethylsulfate, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, Adipic acid, p-
Toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid,
Examples thereof include terephthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid and ascorbic acid. The proportion of the above cyclic acid anhydride, phenols and organic acids in the printing plate material is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, and particularly preferably 0.1 to 0.1% by mass. It is 10% by mass.

In the recording layer coating liquid according to the present invention,
To extend the stability of processing under developing conditions, Japanese Patent Laid-Open No.
Nonionic surfactants as described in JP-A-2-251740 and JP-A-3-208514, and amphoteric as described in JP-A-59-121044 and JP-A-4-13149. Surfactant, EP950
A siloxane-based compound as described in Japanese Patent Application Laid-Open No. 517/517 and a fluorine-containing monomer copolymer as described in Japanese Patent Application Laid-Open No. 11-288093 can be added.

Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride and polyoxyethylene nonylphenyl ether. Specific examples of the amphoteric activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N.
-Tetradecyl-N, N-betaine type (for example, trade name "Amogen K": manufactured by Dai-ichi Kogyo Co., Ltd.) and the like. As the siloxane-based compound, a block copolymer of dimethylsiloxane and polyalkylene oxide is preferable, and specific examples include DBE-224, manufactured by Chisso Corporation.
DBE-621, DBE-712, DBP-732, D
BP-534, Tego Glide, manufactured by Tego, Germany
Examples thereof include polyalkylene oxide-modified silicones such as 100. The ratio of the nonionic surfactant and the amphoteric surfactant in the printing plate material is 0.05 to 1
5 mass% is preferable, and 0.1-5 mass% is more preferable.
Is.

In the image-recording layer according to the invention, a printing-out agent for obtaining a visible image immediately after heating by exposure or a dye or pigment as an image colorant can be added. A typical example of the print-out agent is a combination of a compound that releases an acid when heated by exposure (photo-acid releasing agent) and an organic dye capable of forming a salt. Specifically, a combination of an o-naphthoquinonediazide-4-sulfonic acid halogenide and a salt-forming organic dye described in JP-A-50-36209 and JP-A-53-8128, and JP-A-53 / 1983. -36223, 54-74728, 60
-3626, 61-143748, 61-15
Examples thereof include combinations of trihalomethyl compounds and salt-forming organic dyes described in JP-A Nos. 1644 and 63-58440. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent stability over time and give a clear printout image.

As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Suitable dyes, including salt-forming organic dyes, include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink #
312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl. Violet (CI42535), ethyl violet, Rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI5201).
5) etc. can be mentioned. In addition, JP-A-62-2
The dyes described in Japanese Patent No. 93247 are particularly preferable. These dyes are added in an amount of 0.
It can be added to the printing plate material in a proportion of 01 to 10% by mass, preferably 0.1 to 3% by mass. Further, a plasticizer is added to the printing plate material of the present invention, if necessary, in order to impart flexibility to the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid. Oligomers and polymers are used.

The image recording layer of the lithographic printing plate precursor of the invention is
Usually, it can be produced by dissolving each of the above components in a solvent to prepare a coating liquid for the image recording layer, and coating the coating liquid for the recording layer on a suitable support. As the solvent used here, ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy. Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. It is not limited to. These solvents may be used alone or as a mixture.
When selecting the coating solvent, when the image recording layer has a two-layer structure of an upper recording layer and a lower recording layer, the upper recording layer is formed in order to prevent mutual compatibility at the interface between the layers when they are provided adjacent to each other. The coating solvent for the layer is preferably selected so that it does not substantially dissolve the lower recording layer. The concentration of the above components (total solids including additives) in the solvent is preferably 1 to 50% by weight.

Various methods can be used for coating, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. You can As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the photosensitive film deteriorate. In the photosensitive layer according to the present invention, a surfactant for improving the coatability, for example, a fluorine-based surfactant as described in JP-A-62-170950 can be added. The preferable addition amount is 0.01 in the total solid content of the recording layer.
~ 1 wt%, more preferably 0.05-0.5 wt%
Is.

[Support] The support used in the present invention includes a dimensionally stable plate-like material having necessary strength and durability, and examples thereof include paper and plastics (eg polyethylene, Polypropylene, polystyrene, etc.) laminated paper, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate) , Polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal and the like), paper laminated with the above metal or vapor-deposited, or a plastic film.

As the support used in the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate which has good dimensional stability and is relatively inexpensive is particularly preferable. The preferred aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a slight amount of a foreign element, and may be a plastic film in which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel and titanium. The content of foreign elements in the alloy is at most 10% by mass. Aluminum which is particularly preferred in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in terms of refining technology, and thus may contain a slightly different element. As described above, the composition of the aluminum plate applied to the present invention is not specified, and conventionally known and publicly known aluminum plates can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

Prior to roughening the aluminum plate, if desired, a degreasing treatment for removing the rolling oil on the surface is carried out, for example, with a surfactant, an organic solvent or an alkaline aqueous solution. Roughening treatment of the surface of the aluminum plate,
Various methods are used, for example, a method of mechanically roughening the surface, a method of electrochemically dissolving and roughening the surface, and a method of chemically selectively dissolving the surface. As the mechanical method, known methods such as a ball polishing method, a brush polishing method, a blast polishing method and a buff polishing method can be used. Further, as an electrochemical graining method, there is a method of performing alternating current or direct current in a hydrochloric acid or nitric acid electrolytic solution.
Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can be used. The thus roughened aluminum plate is subjected to an alkali etching treatment and a neutralization treatment, if necessary, and then subjected to anodizing treatment if desired to enhance the water retention and abrasion resistance of the surface. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used, and generally, sulfuric acid, phosphoric acid,
Oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodic oxidation cannot be unconditionally specified because they vary depending on the electrolyte used, but generally, the concentration of the electrolyte is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C.
A current density of 5 to 60 A / dm @ 2, a voltage of 1 to 100 V, and an electrolysis time of 10 seconds to 5 minutes are suitable. If the amount of the anodic oxide film is less than 1.0 g / m2, the printing durability is insufficient, or the non-image area of the lithographic printing plate is easily scratched, and the ink adheres to the scratched portion during printing. "Scratch stains" easily occur. After being subjected to anodizing treatment, the aluminum surface is optionally subjected to hydrophilic treatment. Examples of the hydrophilic treatment used in the present invention include US Pat.
No. 714,066, No. 3,181,461, No. 3,
There are alkali metal silicate (eg sodium silicate aqueous solution) processes such as those disclosed in 280,734 and 3,902,734. In this method, the support is immersed in an aqueous solution of sodium silicate or electrolyzed. In addition, potassium fluorozirconate disclosed in JP-B-36-22063 and U.S. Pat. Nos. 3,276,868 and 4,153,461,
For example, the method of treating with polyvinylphosphonic acid as disclosed in the above-mentioned No. 4,689,272 is used.

In the lithographic printing plate precursor of the present invention, a positive type image recording layer is provided on the support in a single layer or two or more layers. If necessary, the support and the image recording layer are provided. An undercoat layer may be provided between (the lower recording layer in the case of a multilayer structure). Various organic compounds are used as the undercoat layer component, for example, carboxymethylcellulose, dextrin, gum arabic, polyacrylate having an alkali-soluble acid group, polyurethane or polyvinyl butyral, and an amino group such as 2-aminoethylphosphonic acid. Having phosphonic acid, phenylphosphonic acid which may have a substituent, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid, and organic phosphonic acid such as ethylenediphosphonic acid, which may have a substituent Organic phosphoric acid such as phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acid such as alkylphosphinic acid and glycerophosphinic acid, glycic acid Amino acids such as and β- -alanine, and hydrochlorides of amines having a hydroxy group such as triethanolamine hydrochloride, may be used as a mixture of two or more. Above all, a copolymer having both a sulfone group and an imide group represented by the general formulas (III) to (VII) described above as the "specific copolymer" that can be contained in the image recording layer is preferable. This subbing layer is, by itself, substantially in the image area /
Although it does not have a discrimination function for the non-image portion, it is also preferable for discrimination. Two or more such undercoat layers may be provided.

The above organic undercoat layer can be provided by the following method. That is, water or methanol, ethanol,
A method in which the above organic compound is dissolved in an organic solvent such as methyl ethyl ketone or a mixed solvent thereof is applied onto an aluminum plate and dried, and an organic solvent such as water or methanol, ethanol, methyl ethyl ketone or a mixed solvent thereof is applied. Is a method in which an aluminum plate is immersed in a solution in which the above organic compound is dissolved to adsorb the above compound, followed by washing with water or the like and drying to provide an organic undercoat layer. In the former method, a solution having a concentration of 0.005 to 10 mass% of the above organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass.
And the immersion temperature is 20 to 90 ° C., preferably 25 to 5
The temperature is 0 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this is ammonia,
The pH can be adjusted within the range of 1 to 12 by using a basic substance such as triethylamine and potassium hydroxide, or an acidic substance such as hydrochloric acid and phosphoric acid. Further, a yellow dye may be added to improve the tone reproducibility of the image recording material. The coating amount of the organic undercoat layer is appropriately 2 to 200 mg / m 2, and preferably 5 to 100 mg / m 2. If the coating amount is less than 2 mg / m2, sufficient printing durability cannot be obtained. The same applies when the amount is larger than 200 mg / m 2.

[Backcoat layer] The backside of the support must have
A back coat is provided if necessary. Such a backco
The organic material described in JP-A-5-45885
Polymer compounds and those described in JP-A-6-35174
Obtained by hydrolysis and polycondensation of organic or inorganic metal compounds
A coating layer made of a metal oxide is preferably used.
It Of these coating layers, Si (OCH₃)_Four, Si (O
C₂H_Five)_Four, Si (OC₃H₇)_Four, Si (OC_FourH₉) _FourKay of etc.
Elementary alkoxy compounds are cheap and easily available,
The coating layer of the metal oxide to be used has excellent hydrophilicity and is particularly preferable.
Good

[Plate Making / Printing] The lithographic printing plate precursor prepared as described above is usually used as a printing plate by a series of plate making steps such as image exposure and development, and printing is performed.
Image recording on the lithographic printing plate precursor is carried out by utilizing the action of heat. For example, a thermal recording head or the like is used to directly perform image-wise thermal recording, or a solid-state laser or semiconductor laser that emits infrared rays having a wavelength of 760 to 1200 nm, a high-intensity flash light such as a xenon discharge lamp, or a photothermal conversion type such as infrared lamp exposure. Exposure can also be used.

The image writing may be either a surface exposure method or a scanning method. In the case of the former, the infrared irradiation method,
This is a method in which high-intensity short-time light from a xenon discharge lamp is applied to the original plate to generate heat by light-heat conversion. When a surface exposure light source such as an infrared lamp is used, the preferable exposure amount changes depending on the illuminance, but normally, the surface exposure intensity before modulation with a printing image is 0.1 to 10 J / cm ² . The range is preferable, and the range of 0.1 to 1 J / cm ² is more preferable. When the support is transparent, it can also be exposed through the support from the back side of the support.
The exposure time is preferably 0.01 to 1 msec, preferably 0.01 to 0.1 msec, and the exposure illuminance is selected so that the above-mentioned exposure intensity can be obtained. When the irradiation time is long, it is necessary to increase the exposure intensity due to the competitive relationship between the generation rate of thermal energy and the diffusion rate of generated thermal energy.

In the latter case, a method is used in which a laser light source containing a large amount of infrared rays is used to modulate a laser beam with an image and scan the original plate. Examples of the laser light source include a semiconductor laser, a helium neon laser, a helium cadmium laser, and a YAG laser. Irradiation can be performed with a laser having a laser output of 0.1 to 300 W. When a pulsed laser is used, it is preferable to irradiate a laser having a peak output of 1000 W, preferably 2000 W. The exposure amount in this case is preferably such that the surface exposure intensity before modulation with a printing image is in the range of 0.1 to 10 J / cm ² , and
More preferably, it is in the range of ^{3 to 1} J / cm ² . When the support is transparent, it can also be exposed through the support from the back side of the support. As a light source of actinic rays used for image exposure, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid laser and a semiconductor laser are preferable.
The emission wavelength is preferably 760 to 1080 nm.

As a developer and a replenisher for the positive type lithographic printing plate precursor for infrared laser of the present invention, an alkaline aqueous solution for a general lithographic printing plate precursor such as a PS plate may be used conventionally. Examples of the alkaline compound used in a known alkaline aqueous solution applicable to the lithographic printing plate precursor of the present invention include:
For example, sodium silicate, potassium, sodium triphosphate, potassium, ammonium, dibasic sodium, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Ammonium, sodium borate,
Examples thereof include inorganic alkali salts such as potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium. In addition, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine,
Organic alkaline agents such as n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, ethyleneimine, ethylenediamine and pyridine are also used. These alkaline agents may be used alone or in combination of two or more. Among these alkaline agents, a particularly preferable developer is an aqueous silicate solution such as sodium silicate or potassium silicate. The reason is that the developability can be controlled by the ratio and concentration of silicon oxide SiO ₂ which is a component of silicate and alkali metal oxide M ₂ O. For example, JP-A-54-62004,
An alkali metal silicate as described in JP-B-57-7427 is effectively used.

Further, when developing using an automatic processor, an aqueous solution (replenisher) having a higher alkali strength than the developer.
It is known that a large amount of lithographic printing plate can be processed without changing the developing solution in the developing tank for a long time by adding the above-mentioned to the developing solution. Also in the present invention, this replenishment system is preferably applied. Various surfactants and organic solvents can be added to the developing solution and the replenishing solution, if necessary, for the purpose of accelerating or suppressing the developing property, dispersing the development residue and improving the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Further, in the developing solution and the replenishing solution, a reducing agent such as hydroquinone, resorcin, sodium salt or potassium salt of an inorganic acid such as sulfurous acid or bisulfite, an organic carboxylic acid, an antifoaming agent, and a water softener may be added. It can also be added.

The printing plate developed using the above-mentioned developing solution and replenishing solution is post-treated with washing water, a rinsing solution containing a surfactant and the like, and a desensitizing solution containing gum arabic and a starch derivative. As the post-treatment when the image recording material according to the present invention is used as a printing plate, various combinations of these treatments can be used.

In recent years, in the plate making / printing industry, automatic developing machines for printing plates have been widely used in order to rationalize and standardize the plate making work. This automatic developing machine is generally composed of a developing section and a post-processing section, and is composed of a device for conveying a printing plate, each processing liquid tank and a spraying device, which conveys an exposed printing plate horizontally while pumping it up with each pump. The processing liquid is sprayed from a spray nozzle for development processing. Further, recently, a method has also been known in which a printing plate is dipped and conveyed by a submerged guide roll or the like in a processing liquid tank filled with the processing liquid for processing. In such automatic processing, it is possible to perform processing while supplementing each processing solution with a replenishing solution according to the processing amount, operating time, and the like. Further, a so-called disposable processing method of processing with a substantially unused processing liquid can be applied.

In the lithographic printing plate precursor of the present invention, an unnecessary image portion (for example, a film of an original film) is obtained on the lithographic printing plate obtained by imagewise exposing, developing, washing with water and / or rinsing and / or gumming. If there is an edge mark), the unnecessary image portion is erased. Such erasing is preferably performed, for example, by applying an erasing liquid as described in Japanese Patent Publication No. 2-13293 to the unnecessary image portion, leaving it as it is for a predetermined time, and then rinsing with water. It is also possible to use a method described in Japanese Patent Laid-Open No. 59-174842, in which an actinic ray guided by an optical fiber is applied to an unnecessary image portion and then developed.

The lithographic printing plate obtained as described above can be subjected to a printing step after applying a desensitizing gum if desired, but when a lithographic printing plate having higher printing durability is desired, Is subjected to a burning process. When burning a lithographic printing plate, before printing
No. 2518, No. 55-28062, JP-A-62-3
It is preferable to treat with a surface-adjusting solution as described in JP-A-1859 and JP-A-61-159655. As the method, with a sponge or absorbent cotton soaked with the surface-adjusting solution, it is applied on the lithographic printing plate, or by immersing the printing plate in a vat filled with the surface-adjusting solution, Application by an automatic coater is applied. Further, making the coating amount uniform with a squeegee or a squeegee roller after coating gives more preferable results.

The coating amount of the surface conditioning solution is generally 0.03 to 0.8.
g / m ² (dry weight) is suitable. The planographic printing plate coated with the surface-adjusting solution is dried if necessary, and then a burning processor (for example, a burning processor sold by Fuji Photo Film Co., Ltd .: “BP-130”).
0 ") and so on. The heating temperature and time in this case depend on the types of components forming the image,
The range of 180 to 300 ° C. and the range of 1 to 20 minutes are preferable.

The lithographic printing plate which has been subjected to the burning treatment can be subjected to conventional treatments such as washing with water and gumming, if necessary, but a surface-adjusting solution containing a water-soluble polymer compound or the like. When is used, so-called desensitizing treatment such as gumming can be omitted. The planographic printing plate obtained by such treatment is applied to an offset printing machine or the like and used for printing a large number of sheets.

[0094]

EXAMPLES The original plate and the method for printing the same according to the present invention will be specifically described based on the following examples, but the present invention is not limited to these examples.

Examples 1 to 7 and Comparative Examples 1 to 5 [Production of substrate] Aluminum plate having a thickness of 0.3 mm (material 1
050) is degreased by washing with trichlorethylene,
Nylon brush and 400 mesh pumice-water suspension
Using this surface, the surface was grained and washed thoroughly with water. This board
Soak in 45% 25% aqueous sodium hydroxide for 9 seconds
Etching is performed, and after washing with water, it is further washed with 20% nitric acid.
It was immersed for 0 seconds and washed with water. The edge of the grained surface at this time
The amount of ching is about 3g / m ²Met. Next, this plate is
Current density of 15A / dm with acid as electrolyte²At 3 g / m²of
After providing a DC anodized film, wash with water, dry and
And 10% at 30 ° C with a 2.5% by weight aqueous solution of sodium silicate.
Second treatment, apply the undercoat solution below, and coat the coating at 80 ° C for 15
It was dried for 2 seconds to obtain a substrate. The coating amount of the coating film after drying is 15 m
g / m²Met.

[0096] (Undercoat) ・ The following compound 0.3g ・ Methanol 100 g ・ Water 1 g

[0097]

[Chemical 10]

[Coating of Image Recording Layer A] Coating liquid 1 for recording layer described below was coated on the above substrate so that the coating amount was 1.60 g / m 2, and then PERFECT O manufactured by TABAI.
Wind Control 7 at VEN PH200
And was dried at 150 degrees for 50 seconds to obtain a lithographic printing plate. The obtained lithographic printing plate precursor immediately after preparation was packed in a packing form, left at room temperature for one week, and then evaluated.

[0099] [Coating liquid 1 for recording layer] ・ Methyl ethyl ketone 20.204 g M, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight, 700   0, made by Sumitomo Direzu) 2.139g ・ Tetrahydrophthalic anhydride 0.100 g ・ Cyanine dye A (the following structure) 0.042 g ・ Fluorosurfactant (MegaFac F176, manufactured by Dainippon Ink and Chemicals, Inc.)                                                     0.035g ・ Fluorosurfactant (MegaFac MCF312 (30%), Dainippon Ink and Chemicals)   Industry Co., Ltd.) 0.070g ・ 3-Methoxy-4-diazodiphenylamine hexafluorophosphate                                                     0.030g ・ Change the counter ion of ethyl violet to 6-hydroxynaphthalene sulfonic acid   0.036g -0.100 g of each of the following compounds 1 to 7 and comparative compounds a to d

[0100]

[Chemical 11]

[0101]

[Chemical 12]

[Evaluation of Performance of Lithographic Printing Master Plate] The lithographic printing master plates of Examples 1 to 7 and Comparative Examples a to d and the additive-free sample (Comparative Example 5) prepared as described above are as follows. The performance was evaluated according to the standard. The evaluation results are shown in Table 1.

[Sensitivity and Development Latitude] The obtained lithographic printing plate precursor was used as a Trendsetter # 3244MT (wavelength 83) manufactured by Creo.
0 nm), main scanning speed: output at 150 rpm, each output from 3 to 12 W
Solid exposure is performed in W increments, and the following developer (conductivity 83 mS / c
m) developed, Fuji Photo Film Co., Ltd. rinse solution FP-2W
Development was performed using an automatic processor ("PS Processor 900H" manufactured by Fuji Photo Film Co., Ltd.) charged with (1: 7), and the exposure amount at which clear (transparency) was obtained was defined as the sensitivity.

[0104] (Developer) ・ Pure water 870.0 g ・ Sorbitol (59.5%) 122.4 g ・ KOH (48%) 61.9 g ・ Pionine D1107 (Nonionic surfactant made by Takemoto Yushi) 0.5 g

After exposure with 9 W at a main scanning speed of 150 rpm using the above setter, 75 mS / cm, 70 mS / cm, 65 mS / cm by blowing carbon dioxide in addition to the developing solution (83 ms / cm).
175 obtained with each developer using 4 levels of cm
The 50% halftone dot area ratio of lpi was determined by the Yule-Nielsen equation from the value measured with a D19C reflection densitometer manufactured by GRETAG, and the variation rate between the developing solutions was observed. The smaller the difference between the fluctuation widths, the better the development latitude, and if the fluctuation width is within Δ5% or less, it is at a practical level. Further, the reproducibility on the plate of 1% halftone dot of 175 lpi was visually evaluated on a 10-point scale (0 none ↔ all 10) to record the difference.

[Printing durability] Using a lithographic printing plate developed with the above developing solution (75 mS / cm), high quality paper was printed on a Heidel KOR-D machine manufactured by Heidelberg. Printing was performed while wiping the plate surface with a cleaner solution (plate cleaner CL2, manufactured by Fuji Photo Film Co., Ltd.) every time 5000 sheets were printed. Table 1 shows the final number of printed sheets. Here, the final number of prints is the number of prints until the photosensitive layer of the lithographic printing plate is thinned and ink is not partially attached, that is, so-called plate fly.

[0107]

[Table 1]

From Table 1, the lithographic printing plate precursor according to the present invention containing the acid-modified polyvinyl acetal resin is shown in Comparative Example 1.
In comparison with ~ 5, it is found that the development latitude and printing durability are excellent. In particular, in the comparative examples in which no additive is added and an unmodified polyvinyl acetal resin is added, it is found that both the development latitude and the printing durability are insufficient.

[0109]

INDUSTRIAL APPLICABILITY The photosensitive image forming material for infrared laser of the present invention containing a polyvinyl acetal resin having an epoxy group and an acid group has a low image forming property of a recording layer using an alkali aqueous solution soluble polymer compound. Is improved, the handling place is not limited, and the stability of sensitivity with respect to the concentration of the developing solution, that is, the development latitude is good, the printing plate is excellent in sensitivity and is suitable for image forming materials for direct plate making, and can be suitably used. Has the effect.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H025 AA04 AA12 AB03 AC01 AC08                       AD01 CB07 CB14 CB28 CB41                       CB43 CB45 CC11 FA17                 2H096 AA06 BA06 EA02 EA04 GA08                 2H114 AA04 AA23 BA02 BA10 DA41                       DA51 EA01 EA03 EA08 FA17                       GA01

Claims (2)

[Claims] 1. An image recording layer containing, on a support, a substance which absorbs light to generate heat, an alkali aqueous solution-soluble resin having a phenolic hydroxyl group, and a polyvinyl acetal resin having an acid group of pKa5 or less. An original plate for lithographic printing characterized by being provided. 2. The polyvinyl acetal resin is 1,2-
Cyclohexanedicarboxylic acid, tetrahydrophthalic acid,
2. The lithographic printing plate precursor according to claim 1, which is a polyvinyl acetal resin having an ester bond group with an organic acid selected from phthalic acid and trimetritic acid.